Many fluids used commercially contain suspensions of solids in the form of micro-sized particles that are difficult to dissolve and even in the presence of suspending agents tend to deposit or salt out of the solution to a greater or lesser degree. In order to maintain such liquid suspensions uniform to be ready for their intended use, agitation must be provided to maintain the solids uniformly distributed throughout the liquid mass.
One example of such a liquid is found in the agricultural industry where liquid fertilizers are used. In recent years various nutritive additives have been incorporated in such fertilizers in the form of micro-sized particles that are relatively insoluble in the liquid. Much thought has been given to problems involved in the storage and handling of these concentrations of plant foods including suspensions, for example, of potassium chloride, which is relatively insoluble in the typical liquid fertilizer carrier. This is true even when as much as 2% of attapulgite clay is used as a dispersing agent. It has been found that unless such a liquid fertilizer composition is agitated from time to time, that the more insoluble components tend to deposit or salt out on the floor of the bulk storage container.
On large farms where these liquid fertilizers are used in large volume, storage tanks 10 feet or more in diameter and 18 feet high are used to contain such suspensions until they can be delivered to spayer means to be distributed to the crops. If the insoluble components are allowed to salt out on the floor of the containers, difficult problems arise requiring periodic cleaning of the containers under difficult circumstances and, of course, due to the salting out process, some nutrients are lost from the fertilizer composition resulting in an uneven application of fertilizer to the crops.
Various agitating means have been proposed for use in the past for maintaining the solids suspended in liquids stored in large tanks, one such agitating means as is shown in the patent to Horton U.S. Pat. No. 3,378,237. Another known agitator that has been used heretofor is the air bubble agitator shown in the John Blue Company catalogue, form 12-GG-2, issued January 1972, copy of which is attached hereto.
While such known devices have been useful, the present invention has been made to provide an improvement on these known agitating means.